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Airtech

Glossary

Daylight

The distance, in the open position, between the moving and fixed tables or the platens of a hydraulic press. In the case of a multidaylight press, daylight is the distance between adjacent platens.


Debulking

Compacting of a thick laminate under moderate heat and pressure and/or vacuum to remove most of the air, to ensure seating on the tool, and to prevent wrinkles.


Delaminate

To split a laminated plastic material along the plane of its layers. Physical separation or loss of bond between laminate plies.


Denier

A numbering system for yarn and filament in which yarn number is equal to weight in grams of 9000 metres of yarn.


Direct Wound Roving

A roving made directly at the bushing that does not go through a roving process. Typical characteristics are single-end roving, coreless, 6-inch diameter centers and no catenary.


Direct-Sized Yarn

Specially formulated sizings on textile yarns that allow them to be resin compatible.


Dispersion

The degree to which the roving separates into discrete bundles after being chopped. Good dispersion is characterised by a bed of bundles that are uniform in width. Poor dispersion is characterised by a wide distribution in the widths of various bundles in the bed. Poor dispersion can cause poor wet-through and wet-out.


Doctor Roll; Doctor Bar

A device for regulating the amount of liquid material on the rollers of a spreader.


Draft

The tape or slope of the vertical surfaces of a mould designed to facilitate removal of moulded parts.


Drape

A property indicating the stiffness of a product. The stiffness of a mat, for example, determines the ease of conformity to moulded surfaces during initial processing.


Dry Laminate

A laminate containing insufficient resin for complete bonding of the reinforcement.


Dry Lay-Up

Construction of a laminate by the layering of preimpregnated reinforcement (partly cured resin) in a female mould or on a male mould, usually followed by bag moulding or autoclave moulding.


Dry Loft

Height of the bed of chopped fibres.


Dry Winding

A filament winding operation in which resin is not used.